1 Field
Apparatuses and method consistent with exemplary embodiments relate to a communication system and transmitting and receiving data in the communication system.
2 Description of the Related Art
Security issues are emerging as the Internet is rapidly spreading. Thus, companies that install a firewall to block visitors from accessing private resources and control external resources which are accessible to employees are increasing.
A large number of schools and companies internally use a local interne protocol (IP) address by using a network address translation (NAT). By using a NAT, various users may access the Internet with a limited number of official IP addresses, and security issues may be advantageously solved since input/output data has to pass through the NAT to change an address. Accordingly, a NAT may be installed as a portion of a router or a firewall.
However, as network environments of users vary, transmission or reception of data depending on a specific protocol may be impossible due to a firewall or the like, and thus an application service based on the specific protocol may not be performed. That is, depending on a network environment of a specific user, a service provider may not provide a specific service to users.